CNC Light Painting: Some Refinements

CNC light painting red stick man no remote shutter

Smaller LED and cutoff added here, but no taped sides or remote trigger yet.

There were some cool light painting effects in the last post, but to truly do any sort of “presentable” light painting, a few things had to change.

To begin with, with the small canvas that I was working with (approximately 2″ x 10″), the light source needed to be smaller.  This was accomplished by using a 2 color LED by itself instead of the flashlight.  As an added bonus, being two colors allowed it to switch colors mid-stroke if needed.  I don’t have this hooked up to switch yet, but it could be a neat effect.

The second thing that would need to change was the fact that my light was constantly on.  If I wanted to draw exclusively in cursive, this might not have been a big deal, but I wanted to engrave in light whatever I could engrave in real life.  This led to a unique solution using the former Y-axis, now acting as the Z-axis, and a limit switch.

I hooked up the 3 VDC power supply in a normally closed (current flows if not pressed) configuration to a limit switch that was attached to my router’s frame as shown below.  The pseudo-Z-axis was then zeroed just out of the range of the switch so that when it increased, it cut the light off.  This made it act just like my router would when engraving something normally in that when the Z-axis was increased, like a drill or mill going higher, the light would turn off.  This is similar to the way this would cause engraving to cease in a traditional engraving operation.  In other words, from a CAD/CAM perspective, there would be little difference between light painting and engraving.

This would have produced some great results as everything could just be drawn in CAD and “engraved” with the camera’s shutter open, however, there was still one element missing.  In order to open the shutter for more than 30 seconds on the Canon T2i that I’ve been using, you have to physically hold the shutter down on the “bulb” setting.  This produced some shaky pictures, so I bought an Infrared remote trigger from Amazon (less than $4 with shipping Edit: over $5 – price seems to be increasing!).  When in “bulb” mode, the camera’s shutter opens with one press and closes with the second.  Perfect for this application since you don’t even have to worry about a tethered connection pulling on your camera.  The only bad thing is that you have to be on the front side of the camera to trigger it, but if it’s put at an angle, one should be able to avoid being in the frame.  I’m looking forward to trying it out!

Be sure to check back for some better results one I have the remote trigger functional.  This technique will hopefully be improving over the next couple of weeks.  For now, enjoy the video of how a stick-man and pac-man was engraved using the limit switch cutoff and LED.  Please note that when making the actual shot, the room would be dark except for the LED.


  1. CNC Light Painting - Hack a Day - pingback on February 11, 2012 at 5:12 pm
  2. Swapping the Z-axis for a “fast 8s” lead screw | JCOPRO.NET - pingback on February 23, 2012 at 11:09 pm

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